SLave is a very simple utility to start SecondLife(tm) with the necessary loginuris to log in to various OpenSim grids.
SLave will create an icon on your system tray where you can right click to start the viewer for a preset grid.
SLave is largely deprecated by smarter solutions like the Hippo viewer and similar viewers. Still, SLave makes login with the official SecondLife(tm) viewer somewhat easier, especially for developers that might want to log in to various development grids frequently.